Modelling and simulation of energy-efficient controllers for pumps within process industry

The submersible pump is one of the major energy-consuming devices on the utility side. This work considers the modelling, simulation, and control of induction motor-driven submersible pump. A non-linear fifth-order model for the motor and a second order for the submersible pump have been used to include nonlinearities such as saturation of magnetic core and eficency of the pump when powered by sinusoidal and VSI-fed voltage source. The discharge of the submersible pump is very difficult to monitor under closed-loop conditions. Hence a discharge estimator is developed based on motor input voltage, line current, and frequency to predict the quantum of water flow under realistic conditions. A closed-loop discharge controller is designed to control discharge without actually monitoring it. A considerable energy savings is obtained in the closed-loop operation.